1. Field of the Invention
This disclosure pertains generally to locating and tracking systems.
2. The Prior Art
Wireless devices of all kinds have been in use for pinpointing objects, people and animals on the surface of the earth, under water, or in space. Some wireless devices also provide navigational information such as whether or not a moving vessel or vehicle is “on course” to its predetermined destination. Radio frequency (RF) location and navigation systems are the oldest, and more recently developed devices function at infrared (IR) and visible wavelengths. Acoustic location and navigation systems such as sonar also exist.
Traditional radiolocation is the process of determining the position of a vehicle, aircraft, or vessel. Radionavigation is the use of radio apparatus, by personnel aboard moving vessels, for the purpose of plotting and maintaining a course.
The simplest method of radiolocation is known as the “directional method” wherein two or more fixed receiving stations, which are separated by a fixed distance, receive radio transmission signals from a transmitter that is mounted on a vessel. The vessel location is determined from the intersection of great circles drawn outward from the receiver station points in the appropriate directions.
A second implementation for determining the position of objects involves radar. The term “radar” is an acronym derived from the words “radio detection and ranging.” Electromagnetic (EM) waves having certain frequencies reflect from various objects, particularly if those objects contain metals or other electrical conductors. Using a transmitter, receiver, and a display at a fixed station, the location of flying objects with respect to the fixed location may be determined by ascertaining the directions from which radio signal are returned, and by measuring the time it takes for an EM pulse to travel from the transmitter to a target and back. However, such radar systems are not useful for tracking a ground moving objects, or objects which have poor EM reflective properties. Additionally, radar systems are not normally useful for differentiating the identity of objects, particularly when there are a plurality of objects.
The most sophisticated radiolocation and radionavigation techniques employ the global positioning system (GPS). The GPS is a network of radiolocation and radionavigation apparatus that operates on a worldwide basis. The GPS system employs several satellites and allows determination of latitude, longitude, and altitude.
Most recently, vehicle location and navigation systems have been adapted to track the location of automobiles using the GPS system. Such systems include sensors which are fixed to the automobile and draw power from either the car battery or a second large power source. The purpose of fixing the automobile tracking sensor to the vehicle is primarily for security reasons. Because one main purpose of the tracking system to locate the vehicle in cases of theft, it is important that the sensor systems of the tracking systems be mounted or otherwise fixed to the vehicle, making such sensor systems not easily removed or transportable from a first object to a second object. Furthermore, because a large power source such as a car battery is normally available to such tracking systems, intelligent power saving or conserving features are not provided.
Accordingly, there is a need for a tracking and locating system and method which provides for a lightweight and portable tracking locator device, which is easily transferable from user to user or object to object, which provides power saving and conserving features associated with the locator device, and which further provides positional information of such locator devices in the form of hypertext markup language pages viewable on the Internet. The present invention satisfies these needs, as well as others, and generally overcomes the deficiencies found in the background art.